In recent years, in a process for assembling and producing various industrial products such as home electronics, and in a process for producing devices such as electronic components, batteries or substrates that serve as components of the above-mentioned industrial products, paste materials that have various functions are coated onto them, and then, they are subjected to heat treatments by use of a heat treatment apparatus. For example, the heat treatment apparatus includes drying furnaces, baking furnaces, cure furnaces, and reflow furnaces. Reflow furnaces are used for soldering in an electronic component-mounting process, etc. Various solvents such as water and organic solvents are mixed into the paste materials in addition to solid contents that are required for final products, in order to adjust the viscosity or performance.
A solvent included in the paste material is released from the paste material to the inside of the heat treatment apparatus through the volatilization and solvent-removing process in the heating step. If the concentration of the volatilized solvents inside the heat treatment apparatus is increased, this possibly leads to various problems. For example, if the concentration of the solvents in the atmosphere inside the heat treatment apparatus comes close to saturation, it may be difficult to dry the object that is subjected to the heat treatment. Therefore, the outside air, a nitrogen gas or other atmosphere gases are regularly or continuously supplied into the heat treatment apparatus, and, simultaneously, the atmosphere inside the heat treatment apparatus and with an increased concentration of solvent is released to the outside.
FIG. 10 is a diagram that illustrates supply of the outside air and discharge of the atmosphere to/from the heat treatment apparatus 1. An air blower 2 supplies the outside air into the heat treatment apparatus 1. An exhaust blower 3 discharges a part of the atmosphere including a volatilized solvent to the outside of the heat treatment apparatus. However, when the solvent is discharged to the outside of the heat treatment apparatus, influences on the environments may be a concern. Therefore, for example, a system disclosed in JP-A-2004-301373 has been known as a method for removing a solvent from an exhaust atmosphere that is discharged to the outside of the heat treatment apparatus.
FIG. 11 is a diagram that illustrates the system disclosed in JP-A-2004-301373. In the disclosed system, a cooler 5, an exhaust duct 6 present outside the heat treatment apparatus, and a mist collector 7 are connected in that order to an exhaust duct 4 inside the heat treatment apparatus of the heat treatment apparatus 1. The cooler 5 cools the exhaust atmosphere that is discharged from the heat treatment apparatus 1, to thus devolatilize the volatilized solvent included in the exhaust atmosphere. The exhaust atmosphere including the devolatilized solvent is delivered into the mist collector 7 through the exhaust duct 6 outside the heat treatment apparatus, and the devolatilized solvent is captured and removed in the mist collector 7. Accordingly, the solvent can be removed from the exhaust atmosphere that is discharged from the heat treatment apparatus 1.